/*
 * Virtio PCI driver - legacy device support
 *
 * This module allows virtio devices to be used over a virtual PCI device.
 * This can be used with QEMU based VMMs like KVM or Xen.
 *
 * Copyright IBM Corp. 2007
 * Copyright Red Hat, Inc. 2014
 *
 * Authors:
 *  Anthony Liguori  <aliguori@us.ibm.com>
 *  Rusty Russell <rusty@rustcorp.com.au>
 *  Michael S. Tsirkin <mst@redhat.com>
 *
 * This work is licensed under the terms of the GNU GPL, version 2 or later.
 * See the COPYING file in the top-level directory.
 *
 */
#define  __SYLIXOS_KERNEL
#include <SylixOS.h>
#include <module.h>
#include <linux/compat.h>
#include <string.h>
#include <system/device/pci/pciBus.h>
#include <system/device/pci/pciMsi.h>
#include <system/device/pci/pciLib.h>
#include <system/device/pci/pciIds.h>
#include <system/device/pci/pciDev.h>
#include "virtio_pci_common.h"

/* virtio config->get_features() implementation */
static u64 vp_get_features(struct virtio_device *vdev)
{
	struct virtio_pci_device *vp_dev = to_vp_device(vdev);

	/* When someone needs more than 32 feature bits, we'll need to
	 * steal a bit to indicate that the rest are somewhere else. */
	return in32((addr_t)(vp_dev->ioaddr + VIRTIO_PCI_HOST_FEATURES));
}

/* virtio config->finalize_features() implementation */
static int vp_finalize_features(struct virtio_device *vdev)
{
	struct virtio_pci_device *vp_dev = to_vp_device(vdev);

	/* Give virtio_ring a chance to accept features. */
	vring_transport_features(vdev);

	/* Make sure we don't have any features > 32 bits! */
	BUG_ON((u32)vdev->features != vdev->features);

	/* We only support 32 feature bits. */
	out32(vdev->features, (addr_t)(vp_dev->ioaddr + VIRTIO_PCI_GUEST_FEATURES));

	return 0;
}

/* virtio config->get() implementation */
static void vp_get(struct virtio_device *vdev, unsigned offset,
		   void *buf, unsigned len)
{
	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
	void __iomem *ioaddr = vp_dev->ioaddr +
				VIRTIO_PCI_CONFIG(vp_dev) + offset;
	u8 *ptr = buf;
	int i;

	for (i = 0; i < len; i++)
		ptr[i] = in8((addr_t)(ioaddr + i));
}

/* the config->set() implementation.  it's symmetric to the config->get()
 * implementation */
static void vp_set(struct virtio_device *vdev, unsigned offset,
		   const void *buf, unsigned len)
{
	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
	void __iomem *ioaddr = vp_dev->ioaddr +
				VIRTIO_PCI_CONFIG(vp_dev) + offset;
	const u8 *ptr = buf;
	int i;

	for (i = 0; i < len; i++)
		out8(ptr[i], (addr_t)(ioaddr + i));
}

/* config->{get,set}_status() implementations */
static u8 vp_get_status(struct virtio_device *vdev)
{
	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
	return in8((addr_t)(vp_dev->ioaddr + VIRTIO_PCI_STATUS));
}

static void vp_set_status(struct virtio_device *vdev, u8 status)
{
	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
	/* We should never be setting status to 0. */
	BUG_ON(status == 0);
	out8(status, (addr_t)(vp_dev->ioaddr + VIRTIO_PCI_STATUS));
}

static void vp_reset(struct virtio_device *vdev)
{
	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
	/* 0 status means a reset. */
	out8(0, (addr_t)(vp_dev->ioaddr + VIRTIO_PCI_STATUS));
	/* Flush out the status write, and flush in device writes,
	 * including MSi-X interrupts, if any. */
	in8((addr_t)(vp_dev->ioaddr + VIRTIO_PCI_STATUS));

#ifndef SYLIXOS
	/* Flush pending VQ/configuration callbacks. */
	vp_synchronize_vectors(vdev);
#endif
}

static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)
{
	/* Setup the vector used for configuration events */
	out16(vector, (addr_t)(vp_dev->ioaddr + VIRTIO_MSI_CONFIG_VECTOR));
	/* Verify we had enough resources to assign the vector */
	/* Will also flush the write out to device */
	return in16((addr_t)(vp_dev->ioaddr + VIRTIO_MSI_CONFIG_VECTOR));
}

static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
				  struct virtio_pci_vq_info *info,
				  unsigned index,
				  void (*callback)(struct virtqueue *vq),
				  const char *name,
				  bool ctx,
				  u16 msix_vec)
{
	struct virtqueue *vq;
	u16 num;
	u64 q_pfn;

	/* Select the queue we're interested in */
	out16(index, (addr_t)(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL));

	/* Check if queue is either not available or already active. */
	num = in16((addr_t)(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NUM));
	if (!num || in32((addr_t)(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN)))
		return NULL;

	info->msix_vector = msix_vec;

	/* create the vring */
	vq = vring_create_virtqueue(index, num,
				    VIRTIO_PCI_VRING_ALIGN, &vp_dev->vdev,
				    true, false, ctx,
				    vp_notify, callback, name);
	if (!vq)
		return NULL;

	q_pfn = virtqueue_get_desc_addr(vq) >> VIRTIO_PCI_QUEUE_ADDR_SHIFT;
	if (q_pfn >> 32) {
	    _PrintFormat("platform bug: legacy virtio-mmio must not be used with RAM above 0x%llxGB\r\n",
			0x1ULL << (32 + LW_CFG_VMM_PAGE_SHIFT - 30));
		goto out_del_vq;
	}

	/* activate the queue */
	out32(q_pfn, (addr_t)(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN));

	vq->priv_type = 0;
	vq->priv = (void __force *)vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NOTIFY;

	if (msix_vec != VIRTIO_MSI_NO_VECTOR) {
		out16(msix_vec, (addr_t)(vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR));
		msix_vec = in16((addr_t)(vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR));
		if (msix_vec == VIRTIO_MSI_NO_VECTOR) {
			goto out_deactivate;
		}
	}

	return vq;

out_deactivate:
	out32(0, (addr_t)(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN));
out_del_vq:
	vring_del_virtqueue(vq);
	return NULL;
}

static void del_vq(struct virtio_pci_vq_info *info)
{
	struct virtqueue *vq = info->vq;
	struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);

	out16(vq->index, (addr_t)(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL));

	if (vp_dev->msix_enabled) {
		out16(VIRTIO_MSI_NO_VECTOR,
		        (addr_t)(vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR));
		/* Flush the write out to device */
		in8((addr_t)(vp_dev->ioaddr + VIRTIO_PCI_ISR));
	}

	/* Select and deactivate the queue */
	out32(0, (addr_t)(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN));

	vring_del_virtqueue(vq);
}

static const struct virtio_config_ops virtio_pci_config_ops = {
	.get		= vp_get,
	.set		= vp_set,
	.get_status	= vp_get_status,
	.set_status	= vp_set_status,
	.reset		= vp_reset,
	.find_vqs	= vp_find_vqs,
	.del_vqs	= vp_del_vqs,
	.get_features	= vp_get_features,
	.finalize_features = vp_finalize_features,
	.bus_name	= vp_bus_name,
	.set_vq_affinity = vp_set_vq_affinity,
	.get_vq_affinity = vp_get_vq_affinity,
};

/* the PCI probing function */
int virtio_pci_legacy_probe(struct virtio_pci_device *vp_dev)
{
    PCI_DEV_HANDLE pci_dev = vp_dev->pci_dev;

	/* We only own devices >= 0x1000 and <= 0x103f: leave the rest. */
	if (PCI_DEV_DEVICE_ID(pci_dev) < 0x1000 || PCI_DEV_DEVICE_ID(pci_dev) > 0x103f)
		return -ENODEV;

#ifndef SYLIXOS
	if (pci_dev->revision != VIRTIO_PCI_ABI_VERSION) {
		printk(KERN_ERR "virtio_pci: expected ABI version %d, got %d\n",
		       VIRTIO_PCI_ABI_VERSION, pci_dev->revision);
		return -ENODEV;
	}

	rc = dma_set_mask(&pci_dev->dev, DMA_BIT_MASK(64));
	if (rc) {
		rc = dma_set_mask_and_coherent(&pci_dev->dev, DMA_BIT_MASK(32));
	} else {
		/*
		 * The virtio ring base address is expressed as a 32-bit PFN,
		 * with a page size of 1 << VIRTIO_PCI_QUEUE_ADDR_SHIFT.
		 */
		dma_set_coherent_mask(&pci_dev->dev,
				DMA_BIT_MASK(32 + VIRTIO_PCI_QUEUE_ADDR_SHIFT));
	}

	if (rc)
		dev_warn(&pci_dev->dev, "Failed to enable 64-bit or 32-bit DMA.  Trying to continue, but this might not work.\n");

	rc = pci_request_region(pci_dev, 0, "virtio-pci-legacy");
	if (rc)
		return rc;
#endif

	// legacy device bar0 type always IO ???
	vp_dev->ioaddr = (void *)PCI_DEV_RESOURCE_START(pci_dev, 0);

#ifndef SYLIXOS
	if (!vp_dev->ioaddr)
		goto err_iomap;
#endif

    vp_dev->isr_type = 0;
	vp_dev->isr = vp_dev->ioaddr + VIRTIO_PCI_ISR;

	/* we use the subsystem vendor/device id as the virtio vendor/device
	 * id.  this allows us to use the same PCI vendor/device id for all
	 * virtio devices and to identify the particular virtio driver by
	 * the subsystem ids */
	vp_dev->vdev.id.vendor = PCI_DEV_SUB_VENDOR_ID(pci_dev);
	vp_dev->vdev.id.device = PCI_DEV_SUB_SYSTEM_ID(pci_dev);

	snprintf(vp_dev->name, 32, "%s%s", virtio_device_type[vp_dev->vdev.id.device], "_pci_l");

	vp_dev->vdev.config = &virtio_pci_config_ops;

	vp_dev->config_vector = vp_config_vector;
	vp_dev->setup_vq = setup_vq;
	vp_dev->del_vq = del_vq;

	return 0;
}

void virtio_pci_legacy_remove(struct virtio_pci_device *vp_dev)
{
#ifndef SYLIXOS
	struct pci_dev *pci_dev = vp_dev->pci_dev;

	pci_iounmap(pci_dev, vp_dev->ioaddr);
	pci_release_region(pci_dev, 0);
#endif
}
